An 18-year-old woman has been convicted of rape after she pinned down a victim during a horrific gang sex attack.

Claire Marsh is thought to be the youngest woman in Britain to be convicted of rape after she also punched the 37-year-old victim in the face and ripped off her top as she was gang-raped on a canal towpath.

A 15-year-old boy, who is too young to be named, forced the woman to have sex, while others in the 14-strong group - including a boy aged 12 - shouted encouragement as the brutal attack unfolded shortly after midnight on 22 July last year.

Marvin Edwards, 18, Brentford, west London, also raped the woman, after she had been thrown into the Grand Union Canal in Ladbroke Grove, west London and dragged out.

Two boys aged 15 and 16 were cleared of the same charge at Blackfriars Crown Court in London.

Judge Timothy Pontius told Marsh's barrister: "She will know that, given that this was a particularly vile and horrific offence of sexual brutality, a substantial custodial sentence is inevitable."

At the start of the two-and-a-half-week trial Richard Whittam, for the prosecution, told the jury Marsh, from Margate, Kent, as female could be convicted of rape because she encouraged it.

The woman's ordeal began when she set off home by the canal after a "lovely summer's evening" with friends.

A young couple approached her to share a cannabis "spliff" but suddenly she was surrounded and robbed before being thrown into the canal.

As she got out they grabbed her and she was raped.

She briefly escaped but was caught by the gang, kicked and punched repeatedly and dragged naked along a gravel path, lacerating her bare skin.

Eventually she fled naked to her home more than a mile away.

Gang members were arrested after a tip-off and DNA evidence proved Edwards' guilt.

Marsh admitted hitting the woman but denied taking part in the sex attack.

She was remanded in custody for reports and will be sentenced at a later date along with the 15-year-old, who admitted rape, and Edwards.

In Context
Claire Marsh was given a seven year custodial sentence in a young offenders' institute for her part in the vicious attack .

Her two co-accused, aged 15 and 18, were sentenced to five years.

Police said it was the gang's need to boast about the crimes which allowed officers to piece together evidence overheard by the public.

Marsh, described by officers as intelligent, is rumoured to have become involved in the gang because of a relationship with one of them and may have been trying to "show off".

Home Office figures show between 1995 and 1999, 18 women were convicted of rape or aiding and abetting it, but most of those were against children.